Arrangements are known for mixing liquids such as chemical suspensions and solutions in seeking to form a mixture in which the volumes of the liquids are in a predetermined ratio. The respective liquids are added successively in a specific order by metering pumps to control the respective liquid volumes and the mixture characteristics. In particular, a first liquid is fed by its metering pump as a continuous flow to a first mixer into which a second liquid is fed by its metering pump for flow as a mixture to the next mixer into which the next liquid is fed by its metering pump, until all the liquids are combined successively in sequence in the continuous flow.
U.S. Pat. No. 4,305,669 (Hope et al.) shows such an arrangement, formed as a liquid filled closed system free from gas or air, that contains successive circuits for continuous mixing of respective liquids fed by metering pumps in critical sequence at successive circuit points into the liquid flow.
U.S. Pat. No. 3,655,166 (Sauer et al.) shows a liquid filled column, divided by flow pressure openable, normally closed valves into successive mixing zones for preparing a photographic emulsion. Respective solutions of gelatine, potassium bromide, and silver nitrate, are fed by metering pumps in critical sequence to the successive mixing zones for continuous mixing and intermittent flow upwardly through the valves, with the mixture exiting from the top of the column.
U.S. Pat. No. 3,779,518 (Koepke et al.) shows a mixing arrangement for preparing a photographic emulsion in which the respective liquids are fed by metering pumps in sequence to successive mixing zones for continuous mixing.
U.S. Pat. Nos. 4,241,023 and 4,334,884 (both Wilke et al.) commonly show a mixing arrangement for preparing a photographic emulsion in which the respective liquids are fed by metering pumps in sequence to successive mixing zones for continuous mixing, but with ripening of the flow between mixing zones.
These known arrangements concern liquid mixture production that requires repeated cycle pumping by metering pumps to inject the liquids sequentially into the flow and displace the flow downstream in continuous manner. However, such repeated cycle pumping produces non-uniform pulsating flow, non-uniform metered liquid volume flow rates, and a mixture whose liquids are not in precise predetermined volume ratio. As each liquid must be metered into the flow at a precise flow rate relative to the others to provide the liquids in the mixture in precise predetermined volume ratio, such non-uniformity is undesirable.
These known arrangements are unsuited for simultaneously combining a plurality of liquids into a mixture in which their volumes are precisely in a predetermined ratio, for dispensing from a dispenser, by batch, rather than continuous, operation.
It is desirable to have a mixing and dispensing system, for simultaneously combining a plurality of liquids to form a mixture in which their volumes are precisely in a predetermined ratio, for dispensing from a dispenser, as a batch operation. It is especially desirable to have an emulsion dilution and delivery system for preparing a predetermined volume mixture batch of a photographic emulsion for dispensing a discrete volume sample thereof as a test coating onto a substrate.